Am I over reacting??

So me and my boyfriend just broke up after almost 2 years because I cant get over this ONE thing. About 6 months into our relationship, my byfriend, or I guess, ex boyfriend, told me that when he was younger, he used to message older girls online and sext with them, and that when we first got together he was having a hard time and messaged one of them because he felt to awkward talking to me about that stuff so early on. Naturally I was a little upset at first becausd I wasnt too fond of my boyfriend talking to girls he used to have sexual relations with when he was upset instead of me, but I let it go because he had done it so early on. There was still a part of me that was really hurt by it though, because we had been friend for a year previous to getting together, I couldnt figure out why he hadnt come to me with his problems. So another 6 months went by and I didnt say anything, but our relationship was being affected by how I was feeling and I new I had to ask him why he hadnt come to me. Knowing I was feeling unhappy in our relationship, he finally told me the real reason. The people he had been messaging that he thought were girls, were transgender and were now males, and at the time he was worried this meant he was gay so he was trying to message them and see if it was true. He said he didnt tell me because he was scared I would think he was gay and leave him. (He grew up very religious home where being gay is not ok which is why it hit him so hard). Being bi myself, I understood how hard it is to figure yourself out and though I was totally pissed that he lied, I got over it and we once again moved on. A few months went by, and he still seemed really insecure about the whole thing, so I decided it was time to bring it up again. This is when he tells me that he actually cheated on his ex girlfriends with the people he was messaging and that the night he messaged them while we were together, it was actually because he was in the mood, but he quickly realized he was being selfish and blcoked the person before it got sexual. This was the biggest fight wed ever had, I couldnt believe he lied so much and about something that big. But even then I decided it wasnt worth losing him over. So we tried moving on, but I just cant. I can't stand the thought that he didnt want me that night and that he wanted someone else, but I'm also not sure if I'm over reacting. It was when we first got together and he very clearly feels horrible about it. Plus, despite the fact he almost did, he didnt actually cheat. Am I being crazy to leave him over this?